Engineering in K-12 schools: Electrical, power systems
Engineers offer practical advice and best practices on how to design electrical, power, and renewable energy systems in K-12 schools.
- Keith R. Hammelman, PE, Vice president, CannonDesign, Aurora, Ill.
- Robert V. Hedman, PE, LEED AP BD+C, Senior associate, Kohler Ronan LLC, Danbury, Conn.
- Pete Jefferson, PE, LEED AP, HBDP, Principal/vice president, M.E. Group, Overland Park, Kan.
- Essi Najafi, Principal, Global Engineering Solutions, Rockville, Md.
- Rodney V. Oathout, PE, CEM, LEED AP, Regional engineering leader/principal, DLR Group, Overland Park, Kan.
- Sunondo Roy, PE, LEED AP BD+C, Vice president, CCJM Engineers, Chicago, Il.
CSE: Describe some recent electrical/power system challenges you encountered when designing a new building or retro-commissioning an existing building.
Hedman: Many of our K-12 new buildings are additions to existing facilities, which are required to be occupied during construction. Life safety systems serving the existing building must be maintained. Typically, extension of the existing fire alarm is not feasible, resulting in two systems. As the strobes may not be synchronized, it is important to maintain visual separation between the two systems.
Najafi: It is always a challenge upgrading an existing electrical service. On a recent elementary school modernization project for the District of Columbia Public School System, we needed to upgrade an existing 800 amp service to 1600 amp. What made the task daunting was the need to install the new board in the same basement location as the existing board. The room was very tight with only a 9-ft ceiling space. To make things more complicated, the underground utility service also needed to be upgraded, and the entire 40,000-sq-ft renovation project had to be completed over the summer break. It took tremendous effort and coordination between the architect, the contractor, the local utility company, and the switchboard manufacturer to pull it off successfully.
Roy: One particular issue that comes to mind was when we provided design management services for a local school district and we indicated the engineer of record (EOR) had to add new local window-mounted air conditioning units as the old building did not easily accommodate a central air conditioning system. There was apparently a miscommunication between the EOR and the contractor (it was a design-build project) to correctly determine existing electrical load calculations, and as the window units were brought on line, numerous circuits overloaded and tripped. The EOR and the installing electrical contractor had to scramble to recheck circuit loading and provide new dedicated circuits. The challenge with renovation projects is that schools many times do not enforce proper as-builts from job order contracting contractors who come in and provide incremental stop-gap fixes and don’t update panel schedules. Over time, no one knows for sure what all is connected to which circuit. This happens more times than anyone wants to admit, and schools unfortunately keep letting this happen, much to everyone’s inconvenience and cost.
CSE: What types of renewable energy systems have you recently specified in a K-12 school? This may include photovoltaics, geothermal systems, etc.
Jefferson: We’re fortunate to live in one of the best states in the country for solar access. So even if we aren’t putting solar arrays into our projects on day one, we try to program future possibilities into the base design. Besides just leaving space or running conduit out of the electrical room, we’ve done solar shading studies to help optimize roof forms and ensure that we’re not diminishing the future value of that space for solar access.
Oathout: K-12 facilities have been an excellent partner for photovoltaic systems. DLR Group has been fortunate enough to be the design partner on several of these types of projects. The future for on-site renewables in the K-12 market continues to grow as the cost for these systems continues to go down and the desire for buildings to become net-zero increases.
Hedman: Most recent projects we have designed include ground source heat pumps, photovoltaics, domestic hot water solar collectors, and earth ducts.
Najafi: We have recently both specified and designed geothermal systems in K-12 schools. We are also currently designing two large high schools that will use geothermal systems, photovoltaics, and solar water heating coupled with rain water harvesting, variable refrigerant systems, high level lighting controls, and displacement ventilation to provide an overall high-performing building.